Process of producing dischargeable dyeings on cotton.



' No Drawing.

JTTO ERNST AND HEINRICH EICI-IWEDE, OF

SIGNORS T FARBWERKE VORM. MEISTER GERMANY.

' MAIN, GERMANY, A oonrom'rron or PATENT carton.

HGCHST-ON-THE-MAIN, GERMANY, AS- LUoIUs & Rt'rNINa, 0F HcSoHs'r-oN-THE- PROCESS OF PRODUCING DISCHARGEABLE DYEINGS 0N COTTON.

To all tuhom it may concern:

. Be it known that we, 'O'rro ERNST, Ph. D.,

chemist, and HEINRICH EICHWEDE, Ph. D.,

chemist, citizens of the Empire of Germany, residing at Hochst-on-the-Main, Germany, have invented certainnew and useful Im-' provements in Processes of Producing Dischargeable Dyeings on Cotton, following is a specification. It is known that by impregnating the fiber with chrysoidin hydrochlorid and then developing and fixing the chrysoidin by a subsequent treatment with, nitrodiazobenzene,

{there can be obtained dyeings on cotton which are capable. of being discharged.

' -N ow according to our present invention such. dyeings. can be produced very advantageously by using monoazo-dyestuffs obtainable by combininga diazotized aminonaphtholsulfonic acid with met-a-phenylenediamin or a derivative thereof. The azodyestuffs most suitable for this new process are those obtained from aminonaphtholsulfonic acids which, after being diazotized,

are still capable of being combined with one molecular proportion of nitrodiazobenzene. These developing dyestuffs are therefore distinguished from the chrysoidins hitherto used, not only by the fact that theyv are sulfonic acids and that they are applied to the fiber in the form of the salts of these acids, but also by the fact that they can be combined with two molecular proportions of nitrodiazobenzene. This is the essential difference and owing to this property the dyestufl's are transformed on the fiber into prodthe nitrodiazobenzene,

ucts of greatly-increased molecular weight, especially as they receive two molecules of thus rendering the dyeings very intense and very fast to washa resultwhich could not be expected 'ing owihg to the presence of thesulfonic acid groups. The dyestuffs containing sulfonic acid groups which, have been hitherto developed in a similar manner are'direct disand poly-azo-dyestufis and are already, as

such, of rather good fastness to washing.

In the present process the good solubility of the dyestuffs in water is of great imporfame; it facllitates their application to the fiber and renders the use of boiling baths unnecessary. The tints obtained by the new process- .vary from reddish-brown to violet-brown copies of this patent may be obtained for Specification of Letters Patent.

of which the five cents ealcluby addressing the "Gommis'sioner Patented Dec. 26', 1911.

Application filed January 26, 1911. Serial No. 604,884.

and are also sometimes-blackish, according to the dyestuffs used. The monoazo body obtained from a diazotized 1:5-, 2:8- or 2 5- aminonaphtholsulfonic acid yields pronounced brown tints of a reddish to violet hue, while the dyestuffs obtained from a 1:8- amino-naphtholsulfonic acid yields blackish-brown tints.

A brown tint of a deep violet hue and capable of being discharged can be obtained by proceeding as indicated in the following example: 10 grams of the azo-dyestuff, pro- .duced by combining diazotized 2:5:7- aminonaphtholsulfonic acid with metaphenylenediamin, are dissolved in the form of its sodiunr salt in water, and the solut1on is diluted to make one liter. The cotton fabric 1s padded with this solution, then dried and passed through a bath prepared in the usual'manner by diazotizing 14 grams of paranitranilin, adding 40 grams of crystallized sodium acetate and diluting the mixture to 1 liter. The fabric is thel, washed, soaped and dried. Thus a deep dark-brown tint of great fastness to soap and capable of being readily discharged, is obtained.

In a quite analogous manner dyeings can be produced by using other chrysoidins obtained by combining a diazotized aminonaphtholsulfonic acid with meta-phenylenediamin or a derivative thereof.

The structural formula of the dyestuff formed on the cotton-fiber by the treatment withv nitrodiazobenzene, is as follows:

Having now described our invention, what ave claim is:

The herein described process of producing dyeings on cotton, fast to washing and capable of being discharged, by applying on the fabric dyestuffs, obtained by combining a diazotized aminonaphtholsulfonic acid- Washington, D. 0.

.r a I It is hereby certifie 1that in Letters Patent N0. 1,012,619, granted December 26, 1911, upon the application of Otto Ernst and Heinrich Eiehwede, of Hficlis'toh-the-Main, Germany, for an improvement in Processes of Prpdueing 'Dischargeable Dyeings en Cotton, an BIIIOX appears in the printed speeifieation requiring correction as follows: In fOliIinlil, line 91, for I N-C1'O(5 -x 1H, read ZV- O H and that the said Letters Patent should bei'ead with this cerreetiou therein that the same may 'eonfenil to the record of the cese the Pateiat Office.

Signed and sealed this 11th day' of June,.A ..D., 19 12.

0. 'c. BILLINGS', riding Comm'ese'bner of Patents.

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